On a GaN-based ion sensitive field-effect transistor (ISFET) with a hydrogen peroxide surface treatment

A GaN-based ion sensitive field-effect transistor (ISFET) prepared by a hydrogen peroxide (H2O2) treatment is fabricated and studied. A 3-nm-thick GaxOy layer formed by an immersion in H2O2 solution is examined and confirmed by EDS and XPS analyses. Experimentally, the studied pH-ISFET presents a higher voltage sensitivity (54.88 mV/pH), a higher current sensitivity (−56.09 μA/pH mm), a lower drift rate (1.41 μA/h mm), an extremely low hysteresis (0.4 mV), and a lower voltage decay rate (−0.14 mV/pH day) after 28 days. Moreover, insignificant interference effects from Na+ and K+ ions were observed. Thus, the studied GaN-based ISFET utilizing an H2O2 treatment promises to fabricate high-performance pH sensing applications.